Heart Rate Monitor Interface

Hey all,

I give a lot of presentations, and I thought it’d be fun to display my heart rate for the audience during the presentations.

I picked up one of the SparkFun Heart Rate Monitor Interface (HRMI) breakouts, which supports I2C (7-bit address). I connected it to the Imp, and after a little tinkering around, I was able to pull my heart rate from the breakout. I thought I’d post the code here for anybody else that might want to use the HRMI breakout. I used a Polar T31 transmitter. The breakout supports both coded and non-coded transmitters, but the non-coded is generally less expensive.

Sampling happens every five seconds. From here I have the Imp HTTP POST the data to a server (PHP on Amazon Elastic Beanstalk), where I store the heart rate data in a database (Parse.com), and then send it along to a Web Socket server (Pusher.com). At that point, anybody viewing a specific web page can watch my heart rate in near-real-time during the presentation. That code is not attached. If there is interest, I can make it available as well.

NIce! Please post the code. The monitor for my elliptical looks like that, so maybe it is compatible. Definitely a project I would work on.

Also, if you aren’t busy at 10PM eastern, it would be really cool to have you demo the project on the Electric Imp Disciples Google Hangout.


That’s a really cool and great idea - it would be cool to combine that with a Melon (or other similar device) to get even more biometrics during a presentation!

Sorry for the lag here - it seems I fried the Imp in trying to make some improvements to the project. I’ll post a link to the code when my replacement Imp arrives. I’d be happy to show the project on the Google Hangout at some point. I’m designing a heart-shaped enclosure for the project that I can clip to my belt during presentations. Might be more interesting to show then. It’s just wires and boards for now.

jwehr, what elliptical do you have?

  • be careful with biometrics in front of an audience. What if someone accidentally or on purpose asks you an embarrassing question ? : ) might show up even more than a red face.